Plesk and sites show: HTTP error 503 - Application Request Routing\requestRouter

[Suhitha]

Question: Plesk and sites show: HTTP error 503 - Application Request Routing\requestRouter.dll failed to load


Symptoms

• Websites are not accessible with HTTP error 503
• PleskControlPanel and most IIS application pools could not be started at IIS > Application Pools.
• Event Viewer > Application log contains the following error under Event ID 2280

Code Select Expand

The Module DLL C:\Program Files (x86)\IIS\Application Request Routing\requestRouter.dll failed to load. The data is the error.

Cause

Microsoft Application Request Routing package corrupted or missing.


Resolution

Download and install Application Request Routing package from Microsoft website: